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Any idea why a random lamp or lamps would pulse when another series of lights are turned On? The lights in our building is on a multi branch circuit, I'm guessing it has something to do with the shared neutral.

Any idea why a random lamp or lamps would pulse when another series of lights are turned On? The lights in our building is on a multi branch circuit, I'm guessing it has something to do with the shared neutral.

Whatever the problem is it's not because the lights are on a multiwire branch circuit. Stop focusing on some superstitious fear that isn't based in reality.

The whole North American Continent is fed with power that shares a neutral. There may be some bad wiring causing problems, but electrons are too dumb to know what circuit conductor they are traveling around on, and LED lamps don't care what kind of circuit they wired to.

Whatever the problem is it's not because the lights are on a multiwire branch circuit. Stop focusing on some superstitious fear that isn't based in reality.

The whole North American Continent is fed with power that shares a neutral. There may be some bad wiring causing problems, but electrons are too dumb to know what circuit conductor they are traveling around on, and LED lamps don't care what kind of circuit they wired to.

I think it's far more likely that cheap LED lamps are the problem.

Thanks for the reply Dave. I'm getting this random flicker on several rooms. I know it could be a possible wiring issue, but I can't believe that many are wired bad. I have personally wired a few offices by myself and feel they are all correct. I have also tried a Phillips 17w type B with the same flickering results.

Once all lights are on I have zero problems. The only time I have a problem is when a set is turned on, an existing set will have a random flicker on 1 or a few lamps. I can't say it's always the same lamp and sometimes it doesn't happen at all.

You clearly have a single shot transient problem that only occurs at some turn on time. To light an LED for a moment it takes some amount of energy.

You have lights that are turned on and off by some sort of switch. What is the actual switching device between power (the hot wire) and the actual lights that flash when some other circuit is turned on? Is it an ordinary mechanical wall switch, mechanical contacts on a relay, or some sort of electronic switch?

How long are wire runs where hot and neutral wires are close together? A 4 ft long LED bulb will take a moderate amount of energy for a momentary flash. Could a 1000 pfd (0.001 ufd) capacitor provide enough energy?

An LED driver probably has a fairly large input capacitor with little current limiting in series. After being off this capacitor has near zero stored charge. If turn on to this capacitor occurs at an AC voltage peak, then you can expect a large input current spike at this turn on.

How could such a large current spike couple to what you think is an unconnected LED? Also there are likely large voltage spikes.

You clearly have a single shot transient problem that only occurs at some turn on time. To light an LED for a moment it takes some amount of energy.

You have lights that are turned on and off by some sort of switch. What is the actual switching device between power (the hot wire) and the actual lights that flash when some other circuit is turned on? Is it an ordinary mechanical wall switch, mechanical contacts on a relay, or some sort of electronic switch?

How long are wire runs where hot and neutral wires are close together? A 4 ft long LED bulb will take a moderate amount of energy for a momentary flash. Could a 1000 pfd (0.001 ufd) capacitor provide enough energy?

An LED driver probably has a fairly large input capacitor with little current limiting in series. After being off this capacitor has near zero stored charge. If turn on to this capacitor occurs at an AC voltage peak, then you can expect a large input current spike at this turn on.

How could such a large current spike couple to what you think is an unconnected LED? Also there are likely large voltage spikes.

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The switch is an ordinary wall switch. Last week I turned all the lights on that run off the same panel and fired a few compressors from the RTUs. The lights didn't flicker or react in any way. I have plenty of slack between wires feeding the fixture and tombstones. Could that be a problem, too much wire?
If there are large spikes, how would I prevent this?

(1) How many different LED fixtures in one room?
(2) How many different switched LED circuits in one room?
(3) How many switches in one box?
(4) How many different switching locations are in one room?
(5) How big is the room?
(6) Are all the lights in one room on the same phase?
(7) Are all the LEDs controlled by one switch close together in the room or scattered amongst LEDs on other switches?
(8) If you toggle on and off one circuit of LEDs what percentage of time does an LED flash in another circuit? Is it always in the same other circuit?

What does a tombstone have to do with the problem? I think that you can consider a single fixture when disconnected from its supply wires at the fixture to have almost zero likelihood of flashing from adjacent wires.

(1) How many different LED fixtures in one room?
(2) How many different switched LED circuits in one room?
(3) How many switches in one box?
(4) How many different switching locations are in one room?
(5) How big is the room?
(6) Are all the lights in one room on the same phase?
(7) Are all the LEDs controlled by one switch close together in the room or scattered amongst LEDs on other switches?
(8) If you toggle on and off one circuit of LEDs what percentage of time does an LED flash in another circuit? Is it always in the same other circuit?

What does a tombstone have to do with the problem? I think that you can consider a single fixture when disconnected from its supply wires at the fixture to have almost zero likelihood of flashing from adjacent wires.

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12 fixtures per room, each fixture has 2 lamps.
2 circuits per room, most rooms are divided in half, some thirds
2 single pole switches per box.
Rooms are 30'x30'
They share the same circuit the ones I turn on and the ones that Flickr
They flicker immediately as the lights are powered.
I don't have any dimmers or 3ways.

Tombstones have nothing to do with it, I was just stating my 18 gauge in the fixtures may be fairly long with hot and neutral possibly close together.

To get electrical energy to a load you need some sort of closed electrical circuit (excluding radiated radio frequency energy, I think we are only concerned with conductive, capacitive, and inductive components describing your circuit).

Assuming your switches are really open when off, then to get energy to the flickered fixture means there has to be some form of capacitive or inductive coupling to the flickered circuit.

A very remote possibility is a very large transient voltage at the switch box that causes electrical breakdown of the open switch. I view this as a zero likelihood.

I don't believe there is inductive coupling.

Very likely you have capacitive coupling. You might have 20 pfd per foot between some wires. At most it is unlikely you have more than 60 ft of two hot wires from different circuits this closely coupled. Suppose you did, then the capacitance is 1200 pfd. Can I cause a flicker in a fixture with this amount of coupling? Depends. With sufficient voltage it might be possible.

I don't know your voltage. But get a 0.1 ufd capacitor or somewhat larger of sufficient voltage rating for your circuit voltage. Connect this capacitor between neutral and the hot wire to the fixtures that flicker on the output side of the switch that is off. The connection might be made at the switch box or anywhere near a fixture. See if this eliminates or in any way changes the flicker. This creates a capacitive voltage divider that should greatly reduce the source of voltage to a fixture, if capacitive coupling is the problem.

If capacitive coupling is yor problem, then you need to change the way wiring is run.

To get electrical energy to a load you need some sort of closed electrical circuit (excluding radiated radio frequency energy, I think we are only concerned with conductive, capacitive, and inductive components describing your circuit).

Assuming your switches are really open when off, then to get energy to the flickered fixture means there has to be some form of capacitive or inductive coupling to the flickered circuit.

A very remote possibility is a very large transient voltage at the switch box that causes electrical breakdown of the open switch. I view this as a zero likelihood.

I don't believe there is inductive coupling.

Very likely you have capacitive coupling. You might have 20 pfd per foot between some wires. At most it is unlikely you have more than 60 ft of two hot wires from different circuits this closely coupled. Suppose you did, then the capacitance is 1200 pfd. Can I cause a flicker in a fixture with this amount of coupling? Depends. With sufficient voltage it might be possible.

I don't know your voltage. But get a 0.1 ufd capacitor or somewhat larger of sufficient voltage rating for your circuit voltage. Connect this capacitor between neutral and the hot wire to the fixtures that flicker on the output side of the switch that is off. The connection might be made at the switch box or anywhere near a fixture. See if this eliminates or in any way changes the flicker. This creates a capacitive voltage divider that should greatly reduce the source of voltage to a fixture, if capacitive coupling is the problem.

If capacitive coupling is yor problem, then you need to change the way wiring is run.

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Thanks, I there a reason why this problem didn't occur with the ballast and t12? Will this capacitive coupling cause any future problems, other then the random flicker when lights are turned on?